Contiguous Visual and Brain Stem Auditory Evoked Potential Recordings of Premature Infants

Abstract

This project investigated the maturation and the development of the premature infant's brain by an objective method used in adult and children's diagnoses of brain function, that of the evoked potential. Brain stem auditory evoked potentials (BAEPs) and visual evoked potentials (VEPs) were contiguously and serially recorded from 1 to 4 times on premature infants on the neonatal intensive care unit (NICU). The infants had a mean birthweight of 1168.5 grams (g) and a mean post menstrual age (PMA) at birth of 28.5 weeks. All infants were recorded as soon after birth as was clinically feasible; they then were recorded until discharge from the NICU. Discharge for the majority of the infants occurred at about 36 to 37 weeks conceptual age (gestational age or PMA plus post natal weeks). The BAEPS and VEPS were correlated with ultrasound scans in an attempt to isolate known structural damage with a possible tool for measuring functional damage within the brain. Almost one half of the population investigated sustained a haemorrhage within the brain during their stay on the NICU. It was hypothesized that abnormal wave morphology, amplitude or synchrony of the BAEP and/or VEP recordings might show functional damage within the brain which would correlate with ultrasound findings of structural brain damage. Twelve hypotheses were tested. A significant difference was found between the haemorrhage group and the non haemorrhage group when analysed by VEP maturational wave latency decreases over time. The groups differed significantly at the (P< 0.005) level. The non haemorrhage group's VEP negative wave latencies decreased at a significantly faster maturational rate than did those of the haemorrhage group. There was no statistical difference found between the haemorrhage and non haemorrhage groups' BAEPs' wave V latencies over time.